1. Q: What conditions are included in hydrocephalus? How should it be treated?
A: There are three main types of hydrocephalus commonly seen. It should be noted that not all hydrocephalus needs to be treated surgically as soon as possible, and parents should choose according to the specific condition.
First, acute hydrocephalus, requiring emergency surgical treatment Ma Jie, Department of Pediatric Neurosurgery, Shanghai Xinhua Hospital
Acute hydrocephalus with progressive brain herniation, i.e., sudden obstruction of cerebrospinal fluid pathways, leads to an increase in intracranial pressure, and within a few hours there is an enlargement of the ventricular system adjacent to the obstruction. If the cranial suture has closed, the intracranial pressure will rise progressively and rapidly. If not treated quickly, the child will die quickly.
Causes of acute hydrocephalus include: spontaneous intracranial (intracerebroventricular) hemorrhage, posterior cranial fossa tumors, acute exudative meningitis, traumatic brain injury, and acute ventricular drainage disorders.
Second, chronic hydrocephalus, with optional surgical treatment or follow-up
Children with chronic hydrocephalus have no significant or slowly enlarging ventricles. This hydrocephalus may be associated with a number of compensatory mechanisms that slow or halt progression and generally occur when the ventricles are not completely obstructed.
These compensatory changes include expansion of the skull (when the cranial sutures are not closed), decreased intracranial blood volume, and extensive enlargement of the ventricular system together with shrinkage of brain tissue.
Third, resting hydrocephalus, follow-up is sufficient
A resting hydrocephalus can be defined as a chronic hydrocephalus in which the cerebrospinal fluid pressure returns to normal values during the course of the disease, with normal intracranial pressure.
In compensatory or “resting” hydrocephalus, the rate of cerebrospinal fluid absorption is the same as the rate of cerebrospinal fluid production, and the size of the ventricles remains stable or even shrinks. No new neurological signs appear, and there is evidence of improvement with age.
2. Q: How is hydrocephalus differentially diagnosed?
A: The initial diagnosis of hydrocephalus is based on the rapid increase in the head circumference of the child, which is a very typical symptom.
However, other causes can also cause changes in head circumference to increase. In diagnosing hydrocephalus, the following conditions need to be distinguished from.
First, familial macrocephaly: the only symptom is an increase in head circumference, with no other underlying symptoms. Usually, there are other members of the child’s family with enlarged head circumference, and this symptom can be seen as a family-specific “sign”. It is usually associated with benign extracerebral effusion in infants and does not require treatment.
Second, benign infantile extracerebral fluid: Due to the accumulation of cerebrospinal fluid on the convex surface of the brain, the child’s head circumference increases at an abnormally fast rate within a few months of birth, gradually approaching the rate of children of the same age in the first 15-18 months of life. Physical examination and growth are usually normal. However, there are some children with mild and transient developmental delays in their ability to move.
Other possible causes of this benign effusion include benign infantile subdural effusion, benign traffic hydrocephalus, idiopathic periaqueductal swelling, benign enlargement of the subarachnoid space, hypodense extracerebral fluid accumulation, pseudohydrocephalic giant skull, extraventricular obstructive hydrocephalus, benign hydrocystic tumor, and subarachnoid exudate.
This benign infantile extracerebral fluid accumulation is a benign, self-limiting condition that usually presents between the ages of 1 and 3 years. At 2 to 3 years of age, it resolves on its own. Such disorders rarely require surgical intervention, and surgery is also a secondary option for children presenting with motor delay, elevated intracranial pressure, and fluid accumulation.
Third, chronic subdural hematoma or acute attacks of chronic subdural hematoma: the only symptom is an increase in head circumference with no other underlying symptoms. There is also an enlarged head circumference that is hereditary, a condition that is unique to the family, which is usually associated with benign infantile extracerebral effusions.
3.Q: How is hydrocephalus treated?
A: There are two common treatment options for hydrocephalus: cerebrospinal fluid shunts and endoscopic third ventriculostomy (ETV).
Cerebrospinal fluid shunt: The most common treatment for hydrocephalus requires surgical placement of a shunt, which is a flexible, elastic tube.
The upper end of the shunt is placed in the fluid space of the ventricles within the brain. This tube is connected to a valve to control the flow of cerebrospinal fluid through the shunt. The shunt drains the cerebrospinal fluid under the skin to a place where it can be absorbed by the body. One of these areas is the lining of the abdominal cavity (peritoneum). This is called a ventriculoperitoneal shunt (VP shunt).
In less common cases, the shunt connects from the brain to other parts of the body: for example, the shunt that connects from the brain to the lungs around the chest (pleural cavity) is called a ventriculothoracic shunt. A shunt that connects from the brain to a vein in the heart for discharge is called a ventriculo-atrial shunt.
Endoscopic third ventriculostomy (ETV): This is a second type of procedure performed in some children with hydrocephalus. In a fistula, the surgeon makes an opening at the base of the middle ventricle of the brain so that cerebrospinal fluid no longer accumulates in the ventricles, but can flow in and around the brain as it would in normal cerebrospinal fluid.
This means that the child will not need a shunt, but will rely on the fistula made by the surgeon during the procedure to ensure the flow of spinal fluid. After surgery, it remains very important to watch the child’s brain pressure to see if it increases again. This is because fistulas at the base of the ventricles can fail or become obstructed. If the hydrocephalus recurs and the child’s head circumference increases again, the child can still be readmitted for a cerebrospinal fluid shunt, which means that failure after ETV can be followed by a shunt.
ETV is mainly indicated for non-traffic hydrocephalus because there are two prerequisites for successful fistulotomy: the patient’s ability to absorb cerebrospinal fluid normally; and smooth circulation of cerebrospinal fluid in the subarachnoid space. Therefore, the selection of patients with different etiologies of hydrocephalus has a direct impact on the outcome of the procedure.
Overall, obstructive hydrocephalus can achieve a more satisfactory surgical success rate through ETV. Among them, the surgical success rate of obstructive hydrocephalus due to stenosis of the middle cerebral aqueduct, parietal and thalamic tumors, posterior cranial fossa tumors, tumors in the pineal region, cervical medullary spinal bulge, and cysts is 83%-95%. Therefore, obstructive hydrocephalus caused by any occupancy between the posterior half of the three ventricles and the exit of the four ventricles is the best indication for triculostomy.
For hydrocephalus, other adjunctive treatments are: medical treatment and surgical removal of the lesion.
One of the goals of medical treatment is to reduce the rate of cerebrospinal fluid formation. Acetazolamide can be used to slow down the rate of cerebrospinal fluid production in children with a mild discrepancy between the rate of cerebrospinal fluid production and the rate of reabsorption Acetazolamide is most commonly used for benign extra-axial cerebrospinal fluid collections and also for postoperative transient meningitis (which often leads to impairment of cerebrospinal fluid absorption).
The second aim of internal treatment is to open the cerebrospinal fluid circulation pathway. If steroids are used, the obstructive hydrocephalus caused by brain tumor adhesions can be controlled for a short period of time. It is presumed that this may be due to the fact that steroids can reduce the peri-cancerous tissue edema and shrink the lesions that obstruct the pathway, and may also have the effect of slowing down the secretion of cerebrospinal fluid.
Surgical removal of lesions: With the development of technology and experience, it is now believed that for obstructive hydrocephalus with brain tumor lesions, first surgical removal of tumor tissue is the preferred treatment option.
4.Q: What are the precautions after shunt or ETV?
A: Whether it is shunt or ETV, if you find that it is not working properly after surgery, please seek medical attention immediately. This is because it will re-impose stress on the brain. Signs of poor post-shunt or ETV are the same as signs of hydrocephalus. Your child may have the same symptoms as before the shunt was placed, or may have new symptoms.
Also, it is important to prevent infection after surgery, including the following: swelling or redness around the skin and incision where the shunt was buried, fever, stiffness in the neck, fluid coming out of the incision, loss of appetite or poor diet, general feeling of discomfort and headache.
5.Q: What are the advantages and disadvantages of each compared to bypass and ETV?
A: Shunt is to put a shunt into the body to divert the fluid in the ventricles to other parts of the brain, while ETV is to create a fistula at the bottom of the three ventricles, that is, to open another pathway for cerebrospinal fluid circulation, so as to relieve hydrocephalus. The advantage of shunting is that it is more definitive and can immediately divert the fluid from the ventricles. The disadvantage is that a foreign body is placed inside the body and some patients may have a rejection reaction, and there is a risk of complications such as infection, ventricular fissures, and excessive shunting at follow-up. The advantage of ETV is to open another channel in the body, which is close to the physiological situation without foreign body; the disadvantage is that it is effective for obstructive hydrocephalus, but only 50% effective for traffic hydrocephalus, and some patients will have recurrence of hydrocephalus when the fistula is closed again.
6.Q: Can I do ETV again after having a shunt?
A: Children who have undergone shunt surgery can undergo ETV if there is infection and shunt tube dysfunction.